Comparative study of GaAs and GaInNAs/GaAs multi‐quantum well solar cells

<jats:title>Abstract</jats:title><jats:p>Current–voltage (<jats:italic>I</jats:italic>–<jats:italic>V</jats:italic>) characteristics together with spectral quantum efficiency (QE) measurements are performed on a GaAs control and GaInNAs/GaAs multi‐quantum well (MQW) solar cell under illumination with the AM1.5G spectrum. Nitrogen and Indium composition in the GaInNAs wells were selected as to ensure lattice matching to GaAs. The wells are shown to extend the spectral response to longer wavelengths but also cause a reduction in the QE at wavelengths below the GaAs band gap. Furthermore, the addition of wells generally causes a large decrease in open circuit voltage due to the increased dark current. The MQW cell reaches an efficiency of 5% compared to 8.5% for the GaAs control cell.</jats:p>